[evlatests] Status

[Rick Perley]

    We ran a quick check over lunch today. 

    A)  Global Issues.

    We still have the bad first-record problem at all bands whenever the 
frequency is changed.  However, the end-of-scan bad data problem seems 
to be absent. 

    As noted before, some IFs following a U-band observation do not set 
up correctly.  These data are not flagged. 

    B)  'Erroneous' flagging.  We have many examples of this problem.  
In some cases, the flags are probably set for a valid reason, but as the 
data look fine, we may be too stringent in our tolerances.
         At P-band, 19B was flagged throughout, but the data seem fine. 
         At L-band, 17C was flagged, but looks fine. 
         At C-bnd, 14B and 1D were flagged, but seem fine.
         At X-band, 1D (ditto the above)
       
    C)  At K and Q bands, we have flagging of a type I've not seen 
before.  For one or both observations made at each band, large numbers 
of antennas -- both VLA and EVLA, are flagged as bad, but in fact appear 
to be perfectly good. 
            At K-Band, either or both scans from antennas 1, 2, 8, 11, 
12 13 14 15 16 24 and 27 are flagged.  In most cases, all four IFs are 
flagged, but for some of these antennas, it is one, or two IFs which are 
flagged. 
            At Q-band, antennas 1, 11, 13 16 19 20 and 25 were flagged, 
in all four IFs, in one scan.  The other scan was unaffected.  As for 
the others, the flagged data appear perfect good. 
            I have no clue as to what went wrong here. 

   D)  Sensitivity problems.  Very few noted:
          1) P-Band:  28C and D down by a factor ~2.
          2) X-Band:  Antenna 8, all IFs, low by a factor at least 2. 
          3) K-Band:  Antennas 19, 24, and 25 are low, by factors of 
2.5, 1.5 and 3.5, respectively, in all four IFs.
          4) Q-Band:  Antennas 18 and 20 low by a factor of ~2. 

   
    Otherwise, there were no noted phase jumps of any kind.  A few 
changes in correlation coefficient between consecutive scans at the same 
band were seen -- undoubtedly due to system temperature changes of 
unknown origin -- this has been reported before, and awaits 
explanation.  (The changes are not large, so this is not a worrisome 
issue at this time).